Immunological functions of the mucosal tissues Flashcards
Explain characteristics of both the innate and adaptive immune system
Innate:
-prevents infection and avoids disease
-non specific
-no memory
-mediated by: macrophages, epithelial barriers, secretions
Adaptive:
-responds to infection and prevents disease
-highly specific response to targeted microbe
-mediated by: lymphocytes, antibodies etc
Explain systemic immunity and mucosal immunity
systemic immunity:
-bone marrow, spleen, thymus, lymph system, blood circulation
Mucosal immunity:
-mucous membranes (eyes, nose, mouth, lungs, gut, genitourinary tract)
Explain mucosal immune system characteristics
mucosal surfaces are: oral, nasal, lacrimal surfaces, gastrointestinal tract, bronchial tract, Genito-urinary tract and mammary glands.
-All sites are non sterile and colonised by microbes
-main route of entry for infectious microorganisms
-large surface area specialised for absorption
Explain innate mechanisms and adaptive mechanisms
innate mechanisms of protection include:
-mucin peristalsis, antimicrobial peptides and proteins
Adaptive mechanisms are also present:
-mucosal/secretory immune system
Explain the mucosal barriers (innate)
Innately there are natural barriers e.g. the stomach
There is also:
-mucin
-persistalsis
-proteolysis
-microvillus membrane
List all the sources of serum, saliva and local antibodies in the oral cavity
1) lymphoid tissue
2) peripheral blood
3) gingival focus of leucocytes
4) salivary gland
5) crevicular fluid and leucocytes
-crevicular domain
-salivary domain
-saliva
List all the lymphoid cells in the gut
Lymphoid cells in the gut:
1) Intra-epithelial lymphocytes
2) Lymphocytes and macrophages scattered in the lamina propria
3) Peyer’s patches
Explain Peyer’s patches and mucosal immune responses
Peyer’s patch causes an increased antibody response in comparison to no Peyer’s patch
Explain what M cells do
M cells targets for uptakes, they target particles and macromolecules of viruses
List all the mucosal antibodies
Mucosal antibodies:
-predominantly SIgA
-found in all secretions and breast milk
-provide passive immune protection in new born infants
Explain the difference between serum antibody and secretory antibody
serum antibody:
-light chains and heavy chains
-broken down more easily
-4 chains so polypeptide
Secretory antibody:
-broken down after 8 hours
-has a joining dimer
-has a secretory component which enhances ability to aggregate pathogen target
-two antibodies joined.
What is the difference between amino acid sequence IgG and IgA1
IgG:
-more compact DNA sequence
IgA1:
-quite spread out to attach to multiple pathogens
What are functions of the antibodies IgG and SIgA
Binding to microbes and toxins to neutralize them.
Agglutination (clumping): Helps trap and remove invaders.
Inducing inflammation: Signals the immune system to fight infections.
Recruiting immune cells to attack harmful microbes.
Neutralizing viruses inside cells to stop infections.
Helping remove viruses from the body.
Interacting with non-specific factors to strengthen immunity.
What are different approaches to oral immunisation
approaches to oral immunisation:
-attenuated virus
-attenuated recombinant bacterial mutants
-mucosal adjuvants
-liposomes, microspheres
-capsules
-transgenic edible plants
Explain systemic respond to primary and secondary exposure to a pathogen
Primary:
-at the first immunisation, the antibody response is quite slow however at the 2nd immunisation the antibody response skyrockets- this is due to the developed memory cells that recognise the pathogens immediately due to first exposure
Explain the process of oral vaccine delivery using GM plants
1) The Hep B (genetically modified vaccine) surface antigen is transferred from yeast into a plant cell.
2) Potato plants are regenerated from transformed cells
3) Hepatitis vaccine is correctly expressed by potato plants
4) GM potatoes are harvested that contain the hepatitis vaccine
Explain how the concept of oral vaccine production in plants is tested
1) grow plants which express hepatitis vaccine to maturity and harvest edible tissue
2) feed the uncooked tubers to animals or humans to analyse immune response
Explain hepatitis B human clinical results
-the placebo remains stationary
-2 doses causes a small spike in antibody response, increasing slowly within the months
-3 doses shows the most antibody concentration having a sharp increase
Explain oral tolerance
Oral tolerance refers to the mucosal immune system having to recognise whether something is good or bad.
Orally delivered antigens can suppress systemic immunity
What are practical considerations of oral tolerance
-tolerance to dietary foods, breakdown to food allergy
-oral vaccination and safety
-treatment and prevention of autoimmune diseases
What is the site of stimulation of the mucosal immune system
the site of stimulation is usually at specialised sites in GALT (gut), BALT (bronchi) and NALT (nose)
